1. Field of the Invention
This invention relates generally to inflatable thermal blankets and, more particularly, to an inflatable thermal blanket with a multilayer sheet in which, after use, a layer of the multilayer sheet can be detached, thereby enabling the inflatable thermal blanket to be reused.
2. Description of the Related Art
It often is necessary to control a person""s body temperature using means external to the person. For example, it is important to keep a person warm during surgery and to warm the person post-operatively to reduce the risk of hypothermia. 60-70% of surgical persons will experience hypothermia during surgery, if not treated. Many studies have been published showing the detrimental effects of hypothermia that occur during surgery. Such effects include a higher incidence of infections, more bleeding, more adverse cardiac events, higher death rates, slower recovery and longer hospitalizations. One means of preventing or treating hypothermia is the inflatable thermal blanket.
Inflatable thermal blankets have been in clinical use for the past ten years. Such a blanket may be inflated with cooled or warmed air and deployed over a person in need of thermal management where it bathes the person in a flow of cool or warm air. Persons needing thermal management include accidental hypothermia victims, persons with fever and persons undergoing surgery. Numerous research studies have shown that inflatable thermal blankets provide a highly effective and safe mode of thermal management.
In one use, an inflatable thermal blanket is inflated with warm air and placed adjacent a person. Warm air is expelled through a surface of the device that faces the person, creating a warmed environment about the person, thereby reducing and even reversing the transfer of heat from the person to the environment. Inflatable thermal blankets are provided for generalized and specialized uses, for which various inflatable structures have been developed. See, for example, U.S. Pat. Nos. 4,572,188; 5,300,101; 5,300,102; 5,324,320; 5,336,250 and 5,350,417 assigned to Augustine Medical, Inc. and incorporated herein by this reference. With the introduction of the BAIR HUGGER(copyright) family of inflatable thermal blankets by Augustine Medical, Inc., clinicians have been enabled to provide safe and effective thermal therapy to persons in a number of clinical settings, including surgery and recovery.
An inflatable thermal blanket typically includes a surface through which the inflating medium is expelled. Such a surface may include apertures formed in it by a manufacturing process, or may comprise an air-permeable material, for example. The blanket is deployed with the surface facing the person and the thermally-controlled air which inflates the device is exhausted from the blanket, through the surface, toward the person. The temperature of the thermally controlled air can be precisely controlled in order to warm or cool a person.
The majority of inflatable thermal blankets sold today are disposable xe2x80x9csingle usexe2x80x9d products made of polymeric films and non-woven material. Extreme pressure to control costs has forced many health care providers to carefully examine their use of such disposables. In some cases, providers may reuse xe2x80x9csingle usexe2x80x9d blankets which have been in contact with a previous person""s skin and bodily fluids. There is no suitable way to clean and sterilize these xe2x80x9csingle usexe2x80x9d blankets and therefore this practice can transmit infection from one person to another.
In response to the trend toward reuse of medical products, some manufacturers are now providing inflatable thermal blankets made of durable materials which can be cleaned and sterilized between uses. These blankets also appeal to the providers who believe that disposables are not friendly to the environment. However, reusable inflatable thermal blankets also have several draw-backs. First, they are expensive. Second, their durability is severely limited by the high temperatures and strong detergents necessary to clean and sterilize them. Finally, the detergents themselves are environmentally unfriendly.
From the discussion above, it should be apparent that there is a need for an inflatable thermal blanket that can be safely and economically used multiple times on one or more persons without requiring sterilization between uses. The present invention satisfies this need.
Broadly, the present invention concerns an inflatable thermal blanket with a multilayer sheet providing a surface through which air is transferred from the blanket toward a person. Presently, once an inflatable thermal blanket has been used on a person, this surface may be contaminated. Consequently, the blanket must be cleaned and sterilized or discarded. The advantage of a multilayer sheet is that the layers in the plurality of layers that make up the multilayer sheet may be detached from the sheet one or more at a time and discarded. So, following use of the inflatable thermal blanket, the contaminated layer or layers may be removed to render the inflatable thermal blanket ready for use again.
In an example that embodies, but which does not limit, the invention, an inflatable thermal blanket with a multilayer base sheet comprises an inflatable structure formed by attaching a first sheet to a second sheet. An inflation port is provided in the inflatable structure for admitting a stream of thermally-controlled air (e.g., heated or cooled air) into the inflatable structure. The multilayer sheet is assembled from a plurality bf sheets releasably attached together. The multilayer sheet is attached to the second sheet of the inflatable structure. Finally, a plurality of air passageways through the second sheet and the multilayer sheet allow the thermally-controlled air to flow through the inflatable structure. In a preferred embodiment, one or more layers of the multilayer sheet can be removed at one time without detaching the rest of the plurality of sheets. In this way, contaminated sheets can be removed individually, or multiply, and the inflatable thermal blanket can be reused.
Other features and advantages of the present invention should be apparent from the following description of the preferred embodiments, which illustrate, by way of example, the principles of the invention.